1. Field of the Invention
The present invention relates to a data save processing method for a disk storage device which records data on a disk using a head, and the disk storage system, and more particularly to a data save processing method for a disk storage device which predicts the failure of the head and automatically saves the data on the disk face of the head to a disk face of another head, and the disk storage system.
2. Description of the Related Art
Because of recent demands for data computing processing, larger capacities are demanded for medium storage devices for storing data, such as a magnetic disk device and optical disk devices. Therefore the track density and recording density of the disk medium are constantly increasing. Also a decrease in the unnecessary areas of tracks are demanded.
In such a disk device, various preventive measures to protect data are taken for the defects of the head and a storage medium, since data is read/written by the head. For example, the error status is stored in the SMART (Self Monitoring Analysis Report Technology) information within the disk storage device, and this information is notified to the host device when instructed by the host. Based on this SMART information, the host device recognizes the status of the disk device, generates an alarm, and notifies this to the user.
In some cases, a self diagnosis function is provided for the disk device to detect damage of the magnetic head or defects of the storage medium (e.g. Japanese patent Application Laid-open No. H 10-027436 (especially FIG. 1)).
However because of the recent demands for the downsizing of devices, such a disk storage device is also installed in compact servers and mobile equipment (e.g. notebook personal computers, portable AV (Audio/Visual) equipment). Therefore the disk storage device is used in an environment which is vulnerable to the influence of the external environment, such as vibration and temperature change.
In this environment, the heads and the storage devices are especially vulnerable to damage, and require countermeasures. In prior art, however, even if damage to a head is detected, the data on the disk face for the head to read cannot be read, because of the damage to the head, and the data is lost. Since the data capacity on one face of a disk is increasing today, which means that the data volume which could be lost also increases, this problem can no longer be ignored.
In terms of data protection, using a redundant configuration for the disk device by applying RAID technology is one solution, but with this method, where a defect of one head is regarded as a defect of the entire disk device, other non-defective heads cannot be used continuously.